The Smoking, Tobacco, and Cancer Program (STCP), Division Cancer Prevention and Control (DCPC), of the National Cancer Institute (NCI) is establishing the multi-center Community Clinical Trial for Heavy Smokers as cooperative research program to test strategies for heavy smokers (smoking 25 or more cigarettes per day) that: (1) are effective in obtaining long term cessation; (2) are practical to implement on a large scale basis; and (3) employ a community intervention approach, working through major organizations and social institutions capable of influencing smoking behavior in large groups of people. The trial will involve eight Community Intervention Centers (CIC), each contributing a matched pair of communities, with communities within each pair randomized to either the intervention or the control condition. The trial will be conducted in three phases: Phase I, a 12-month planning and protocol development phase; Phase II, a 60-month intervention and evaluation phase; and Phase III, a 18-month analysis phase. Following the approval of the Phase I defined protocol by the STCP, DCPC, NCI, and its Board of Scientific counselors, Phases II and III will be initiated. Only those CIC who are able to fully implement the Phase II protocol will be continued into Phases II and III.